無線射頻辨識系統預防碰撞演算法之設計

An Efficient Anti-Collision Algorithm for RFID System

許文力(Wen-Li Hsu)

指導教授 ： 施再繁

朝陽科技大學/資訊學院/資訊工程系/碩士(2009年)

摘要

近年來，由於無線通訊技術的發展與進步，使得無線設備被廣泛使用在各種領域之中，而無線技術的成熟、手持式設備功能的提昇，更促成行動通訊、行動計算的可行性，前述技術的應用為人們帶來更多的便利性及多元化的服務。無線射頻辨識系統(Radio Frequency Identification, RFID)為無線通訊中一項新興的應用，無線射頻辨識(RFID)系統乃是一種透過無線射頻(RF)技術的自動辨識系統，簡而言之，此項技術是透過無線電波來傳遞識別資料，可用來快速辨識出環境中各種不同用途的tag，透過tag中所預存的資訊來取得所需的各種資料。當多個tag同時傳送它們的唯一識別碼(Unique Identification, UID)給reader時，則會造成辨識上的干擾，造成reader無法準確的辨識出每一個tag的UID，此現象稱之為tag碰撞，故需要設計一個有效預防碰撞演算法，來改善reader的辨識率，以達到快速準確辨識出每一個tag，此為目前RFID重要且熱門的研究議題。
在此論文中，我們提出了一個有效預防碰撞的方法，稱之為bit competed algorithm(BCA)，來改善無線射頻辨識系統辨識上所發生的碰撞問題，進而提昇系統的辨識效能。在我們所提出的方法中，reader會將同時回應請求傳送訊息之tag的UID進行優先權競爭，所利用的技巧為以簡單布林代數的或運算(Boolean OR)進行逐位元(bit-by-bit)優先權競爭。我們進行大量電腦模擬分析，並和已被提出的預防碰撞演算法進行比較，實驗的結果顯示我們所提出的方法可有效改善碰撞問題，提昇系統整體的效能，比其他方法有更佳的效能。

關鍵字

無線射頻辨識系統 ； 讀取器 ； 碰撞 ； 防止碰撞演算法. ； 標籤

並列摘要

Radio frequency identification (RFID) is an automatic identification system working through radio frequency (RF). Tag collision occurs while two or more than two tags deliver their unique identification (UID) to the reader at the same time. Since collision, which would significantly affect the efficacy of RFID, has been one of the major study issues for RFID technology, we have developed a solution, bit competed algorithm (BCA), to solve the collision problem occurred in RFID system and consequently improve the efficacy of RFID. While receiving the UIDs, the reader will identify the tags through Boolean OR operation for bit-by-bit priority competition. The massive computer simulation results and the comparison with other algorithms for collision prevention proved our method can effectively solve the collision problem and improve the efficacy of RFID system.

並列關鍵字

Anti-collision algorithm. ； RFID ； Collision ； Tag ； Reader

參考文獻

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[3] J. H. Chio, D. Lee and H. Lee, “Query Tree-based Reservation for Efficient RFID Tag Anti-Collision,” IEEE Communications Letter, Apr. 2006, vol. 10, no. 4, pp. 236-238.

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